The phenotypic and cytogenetic spectrum of partial trisomy 9

Abstract

A new patient with trisomy for the chromosome segment 9pter----q22 is compared to 19 previously reported cases of partial trisomy 9. Manifestations such as microcephaly, prominent nasal root, bulbous nose, and down-turned corners of the mouth are common to patients with trisomic segments extending from 9p21 to 9q13, while intra-uterine growth retardation, cleft lip/palate, skeletal anomalies, and heart defects are more common with trisomic segments extending through 9q22-9q32. A graphic method illustrates this progression in the partial trisomy 9 malformation spectrum as the triplicated chromosome region extends from bands 9p21 to 9q32. More severe and random defects are observed with complete trisomy 9 or tetrasomy 9p, suggesting an extreme excess of material greatly increases developmental variability.

Case of partial trisomy 9p and partial trisomy 14q resulting from a maternal translocation: Overlapping manifestations of characteristic phenotypes

“…Distinct radiologic abnormalities of the hands, feet, and pelvic bones have also been described [Schinzel, 1979]. Wilson et al [1985] demonstrated that the spectrum of clinical severity in trisomy 9p correlates with the extent of the trisomic chromosome 9 material. Mental retardation is usually present.…”

“…Partial or complete duplication of the short arm of chromosome 9 was reported in approximately 150 cases and has been reviewed previously [Centerwall and Beatty-Desana, 1975;Smart et al, 1988;Wilson et al, 1985;Young et al, 1982]. The trisomy 9p phenotype includes growth and developmental retardation, typical facial appearance and hand abnormalities, most frequently brachydactyly (Tables I and II).…”

The origin and evolution of vertebrate sex chromosomes and dosage compensation

“…Interestingly, chromosome 9, which is orthologous to large parts of the chicken Z, is highly structurally polymorphic in humans (Humphray et al, 2004). Trisomies of human 9p (Wilson et al, 1985), and monosomies of 5q and 18q (which all share homology with the chicken Z), survive to birth (Nusbaum et al, 2005;Boultwood et al, 2010). Moreover, the snake Z chromosome is known to share homology with human 3p21-p24, 7p14-p15, 10p11-p15 and 17q21-q24 (Matsubara et al, 2006).…”

De novo inverted duplication 9p21pter involving telomeric repeated sequences

“…The phenotype of this child is mild according to the partial trisomy 9p malformation spectrum described by Wilson et al [1985]. He had mild psychomotor delay and nearly normal growth, as usually described [Fryns et al, 1979].…”

“…After the original publication by Réthoré et al [1970], trisomy of the short arm of chromosome 9 became a clinically recognizable syndrome. Almost 150 patients with partial or complete 9p trisomy have been reported, but most patients had an unbalanced translocation involving another chromosome [Young et al, 1982;Wilson et al, 1985]. Ten published cases involved a de novo duplication [Chiyo et al, 1976;Baccichetti et al, 1979;Fryns et al, 1979;Zadeh et al, 1981;Cuoco et al, 1982;Motegi et al, 1985;Mattina et al, 1987;Bussani Mastellone et al, 1991;Phelan et al, 1993;Fujimoto et al, 1998], and one case was a direct inherited duplication [Haddad et al, 1996] (Table I).…”